Derivatisation of carbon surfaces has attracted considerable interest in recent years, in particular in connection with attaching molecules to carbon nanotubes.
The derivatisation of carbon may be carried out for a range of purposes which include modification of the surface properties of a carbon substrate, preparation of carbon-epoxy composites and attaching a molecule to a carbon electrode so that it can take part in an electrochemical reaction in an electrochemical sensor or an electrochemical catalyst.
Traditionally, carbon surfaces were modified by vigorous oxidation on the surface leading to the formation of carboxylic, quinonic, ketonic or hydroxylic groups, which were then reacted further with the target molecule. This aggressive process was difficult to control.
A number of procedures have been described for electrochemical induced derivatisation leading to the formation of a single covalent bond between a carbon electrode and a moiety which becomes attached. Examples have included:    electro-oxidation of alcohols, —see Gou et al Chem. Pharm. Bull., vol 44, page 860 (1996);    electro-oxidation of primary and secondary amines—see Barbier et al J. Electrochem. Soc., vol 137, page 135 (1990), Antoniadou et al J. Appl. Electrochem., 1992, vol 22, page 1060 (1992) and Deinhammer et al Langmuir vol 10 page 1306 1994);    electro-oxidation of carboxylates—see C. P. Andrieux et al, J. Am. Chem. Soc., vol 119, page 4292 (1997);    electro-oxidation of hydrazides—see M. A. Hayes and W. G. Kuhr, Anal. Chem., vol 71, page 1720 (1999); and    electro-reduction of diazonium salts—see P. Allongue et al J. Am. Chem. Soc., vol 119, page 201 (1997).
One approach to derivatisation of carbon without electrochemistry is the homogeneous reduction of diazonium compounds in reducing media—see Pandurangappa et al Analyst, vol 127, page 1568 (2002) and Leventis et al, Talanta vol 63, page 1039 (2004). Also in this category is WO2005/066618 (Schlumberger) which describes the diazocoupling of anthraquinonyl and nitrophenyl groups onto carbon nanotubes by means of the reduction of diazonium salts.
U.S. Pat. No. 6,645,455 (William Rice University) discloses derivitisation of carbon nanotubes by exposure to fluorine gas, possibly followed by further reaction to replace fluorine with some other group. Derivatisation of carbon nanotubes has also been carried out using amines or thiols to attach at defect sites of the carbon nanotubes—see Basiuk et al J Phys Chem B vol 106 age 1588 (2002) and Zanella et al J Phys Chem B vol 109 page 16290 (2005). A number of rather esoteric species have been reacted with carbon nanotubes: amongst these are reaction with nitrenes and the attachment of dipyridyl imidazolidene which is an unusual molecule in which a carbene forms part of a large delocalized system and in consequence does not undergo normal carbene reactions, see Holzinger et al Angewandte Chemie. Int Ed vol 40 page 4002 (2001).